Heliographic printing machine



NOV. 5, 1940. I un' 2,220,526

I HELIOGRAPHIC PRINTING MACHINE Filed April 5, 1938 2 Sheets-Sheet l Nov. 5, 1940. L. KLUITMANN HEL IOGRAPHIC PRINTING MACHINE 2 Sheets-Sheet 2 Filed April 5, 1938 /vra Patented Nov. 5, 1940 UNITED STATES PATENT OFFICE Application April 5, 1938, Serial No. 200,263

. In Germany April 20, 1937 Y 3 Claims.

For large outputs heliographic machines are used which work continuously instead of inter-' mittently like the heliographic printing apparatuses. Most of these heliographic printing ma- 5 chines have a more or less'curved glass plate which often constitutes part of a cylinder and over which the illuminating lamps are arranged.

The tracing and printing paper are jointly moved under the glass plate and at the same time pressed against the glass plate by an endless belt maintained under tension.

The heliographic printing machines certainly possess the advantage that a large number of prints can be made therewith in any given unit of time, but they nevertheless are open to the following objection:

It is often necessary to make a relatively large number of prints from one and the same tracing, the number of prints required may-be different for each tracing.

Heliographic printing machines are known which enable several prints to be made successively from the same tracing without it being necessary to reintroduce the tracing each time. These machines comprise a rotary glass cylinder and a glass drum. The tracings are secured with transparent cement or the like either directly on the glass drum or on glass plates which are then fixed on the drum with screws. The objection to these known heliographic printing machines is, that the tracings can only be removed when the machine is at a standstill and this operation takes a considerable time. Consequently, these machines are not suitable for quick, continuous work.

The objections inherent to the known heliographic machines are overcome by the invention which relates to a heliographic machine in which the tracing and the sensitized paper are fed by an endless band or the like under a rotatably mounted glass cylinder in which one or several sources of light are fixed. According to the invention the glass cylinder is equipped with a controllable gripping or clamping device for holding the tracing. If, when the required number of prints has been made, a fresh tracing is to be inserted, it is only necessary to open the gripping or clamping device (without loosening screws or effecting time-consuming manipulations by special means), remove the tracing from which the prints have been taken and clamp a fresh tracing in its place.

Controllable gripping and clamping devices on rotary drums are already known in connection with rotary and offset printing machines, but in heliographic printing machines such devices have not hitherto been employed.

The feature of the invention consists in utilizing for the heliographic printing process details known from rotary and offset printing machines and thereby improving and perfecting this process.

The gripping or clamping device provided according to the invention on the glass cylinder of the heliographic printing machine is preferably arranged in a metal bar which interrupts the periphery of the glass cylinder and is fixed in,

the flanges carrying the glass cylinder. As the metal bar does not allow the passage of the light from the source of illumination, it is advisable to feed the sensitized paper in the form of cut sheets. To effect automatic feed in this instance a device is preferably provided for automatically feeding the single sheets as is known from rotary and off-set printing presses. The drive for this device is preferably derived from the driving shaft of the glass cylinder. However, it is also possible to employ an endless band for conveying the printing paper.

The tracing cylinder can be kept cool, if necessary, by cold air or the like fed through the ends of the tracing cylinder.

The construction of the heliographic printing machine according to the invention presents the great advantage that the service can be made to a great extent automatic. Thus, for example, it is advisable to equip the heliographic printing machine according to the invention with a device for automatically changing the tracings. Such a device is known in connection with rotary printing presses. To enable the heliographic printing machine to be driven by a con tinuously rotating motor, it is advisable to regulate the exposure time, according to the varying density of the tracings, by setting in peripheral direction adjustable screens arranged in the interior of the glass cylinder for regulating the width of the beam of light emanating from the source of illumination. The element for actuating the screens is so constructed and arranged that the adjustment can be effected whilst the machine is running. It is also possible to intensify and weaken the source of light as required whilst the machine is running. However, it is advisable also to regulate the number of revolutions of the cylinder by gearings, resistances .or the like. a An embodiment of the invention is illustrate by way of example in the accompanying drawings, in whichdistance from the flanges 4 a control arm I 8 is Fig. 1 shows a cross-section through a heliographic printing machine in the position after the changing of a. tracing.

Fig. 2 is a longitudinal section through the drum and the device for changing the tracing.

Fig. 3 shows the same machine in cross-section during the tracing change, the tracing being shown separately.

Fig. 4 shows in side elevation the device for changing a tracing.

Figs. 5 and 6 are elevations of a portion of the machine showing the control lever in two difierent positions.

In the drawings designates the rotatably mounted glass cylinder, against which the paper to be exposed and the tracing are pressed by an endless band 2. The band 2 runs over stationary rollers 3 and 4 and is kept taut by the weighted or spring loaded roller 5. In theinterior of the glass cylinder l illuminating lamps 6 are arranged side by side and thin beams can be regulated in width in peripheral direction by screens B in that the screen? is adjusted by means of a hand wheel 9. The upper parts of the two screens 8, which overlap during the adjustment and also the screens themselves are preferably constructed as mirror surfaces. The illuminating lamps 6 and the screens 8 are fixed or mounted in bearings I6, II on the machine frame l2.

The flanges l3, I4 which carry the glass cylinder l are journalled in the brackets l0, (Fig. 2). The periphery of the glass cylinder i is interrupted at one point to afford space for a metal bar l5 also fixed on'the flanges I3, M. In the metal bar IS the gripper shaft I6 is journalled on which several grippers l1 are fixed. On one end of the gripper shaft "5 projecting a. short fixed which serves for controlling the grippers. I9 is a spring which normally holds the grippers in closed position. Cams o'scillatably mounted on the side wall of the machine frame I 2 serve for controlling the grippers. These cams 20 can be brought into operative position by means of a hand operated lever 3| and rollers 32 and 33 mounted thereon. The earns 20 are normally held in their inoperative position by means of springs 34 (Fig. 4). The arrangement (Figs. 5 and 6) is such that the lever 3|, when brought into operative position, is shifted slightly axially relative to the printing drum. This can be attained for example in that the lower end of the lever 3| is laterally resilient whereas its upper end is correspondingly guidedin 'a cam l groove 35 in the side wall of the machine. Pin

36 fixed on the flange l4 of the glass cylinder l serves for returning the lever 3| into its inoperative position after each change of tracing.

A feed table 2| in the form of a hopper is connected with the lever 3| by means of a rodsystem '31. The feed table 2| is oscillatable about pivots 38 mounted on the machine frame.

The tracing is indicated in dash lines in the table.

2| and designated by 22. 23 is the lower closing cap of the feed table 2|. As the cams 26 are shifted into their operative position, that is into the position in which they open the grippers H, the feed table 2| is at the same time shifted out of the position shown in Fig. 1 into its more steeply inclined position shown in Figs. 3 and 4. When the table 2| is in this position, the cams 39 on the closing cap 23 are moved so near the periphery of the glass drum that they lie in the path of the opened grippers l1. and consequently,

the machine.

as these open grippers pass by, the cams 39 are pushed aside and thereby open the closing cap 23 of the feed table 2| and allow the tracing 22 to slide out of the table. When the roller on the lever l6 rolls off the cam 20, the grippers close and hold the tracing tightly on the drum I.

The printing paper is placed in a pile 24 on, The pile 24 is preferably protected by a cover 25 against impinging light. A rubber roller 26 automatically feeds the uppermost sheet 21 from the pile 24 into the machine. This roller is driven by the driving shaft of the drum and automatically becomes operative at a predetermined time. The details of the drive of the rubber roller 26 are not shown in the drawings as in connection with rotary and ofi-set printing machines several types of paper feed drives are known and any of these known types of drive may be employed for carrying out the invention.

The exposed sheet leaving the machine is designated by 28 and is received by a receptacle 29 screened against the penetration of light and provided with a rear wall 30 constructed as closing cap.

The above described heliographic printing machine operates in the following manner.

The grippers H are first opened by'lifting the control lever l8 against the action of the spring is. Hereupon the front edge'of the tracing to be introduced is pushed under the grippers and is gripped by the release of the control lever Hi. If the glass drum is now. rotated in the direction of the arrow, the tracing 22 lays on the periphery of the drum. At the same time a sensitized sheet 21 is brought between the band 2 guided by the cylinder and the tracing on the drum by means of the rubber roller 26 coupled with the drum in a suitable manner and is conducted through the beam of light from the illuminating lamps 6 'between the belt and drum. After having passed throughthe illuminated section, the exposed sheet 28 is conducted into the receptacle 29. As the tracing 22 is stretched on the drum by means of the grippers any number of prints can be made successively from the same tracing. By means of the automatic feed roller 26 a fresh sheet will be fed at the correct moment so that, in the case of electric drive, the machine requires no attendance whatever for the continuous production of like prints.

If, after a suflicient number of prints has been made from a tracing, it is desired to fit a second tracing, this is first placed in readiness on the feed table"2|. At the time when the change of tracing is to take place the two cams 20 are brought into operative position by the hand operated lever 3| in the manner above described so that the free end of the control lever 8 during the rotation of the drum I, first runs onto the lower and then on to the upper cam, and the grippers H are opened each time when the grippers open the first time, the clamped tracing 22 is liberated and, as the drum continues to rotate, slides on to a separate delivery table 20 are returned. into their'inoperative position,

whereupon prints can be taken continuously from the new tracing until the cams II are again brought into their operative position for en another change of tracing.

I claim: I

1. In a heliographic printing machine of the type including a tracing sheet hopper shiftable into feeding position, a longitudinally slotted glass cylinder rotatably mounted on the framework of 10 said machine, a tracing sheet about the periphery of said cylinder, gripping means in the slot of said cylinder for engaging said tracing sheet, a stationary source of light in said cylinder, means for feeding printing paper to said cylinder, and

15 means for rotating said cylinder in one direction;

the improvement which consists in means for releasing said tracing sheet and replacing the same with a new tracing sheet during rotation of said cylinder, comprising a rockable control arm for said gripping means carried by said cylinder, a

said cams in inoperative position, a lever on the framework of the machine, operatively connected to said hopper, said lever being rockably and axially shiftable with respect to said cylinder for rocking said cams into operative position, to successively actuate said control arm, and for shift- 1113 said tracing sheet hopper into feeding position, and means on said cylinder cooperating with said lever for returning the latter to normal inoperative position.

2. Apparatus as claimed in claim 1 wherein the cam surface of one of said cams is provided with a dwell to retain said gripping means in released position for the introduction of the tracing sheet fed from said hopper.

3. Apparatus as claimed in claim 1 wherein one of said cams is operative only to release the tracing on the cylinder, and the cam surface of the other of said cams is provided with a dwell for retaining said gripping means in released po- 20 sition during the introduction of the tracing sheet from said hopper.

LEO KLUIIMANN. 

